1. Field of the Invention
The present invention relates to a pretensioner that increases tension of a webbing belt configuring a seatbelt device of a vehicle in a vehicle rapid-deceleration state or the like, and relates to a pretensioner manufacturing method for manufacturing such a pretensioner.
2. Related Art
In a seatbelt device disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-313313, a pressurized gas generator is mounted in a tube shape cylinder (called “pipe” in JP-A No. 2000-313313) configuring a pretensioner at one end of the cylinder. When the pressurized gas generation device is activated and thus internal pressure of the cylinder is increased, plural rolling elements, which are accommodated in a line in the cylinder, are sequentially pushed out from the other end of the pipe by such increased internal pressure. The rolling elements are pushed out, and then press a linear or beltlike tension medium.
Thus, a pulley of a clutch wound with the tension medium is rotated in a winding direction, and then the clutch is connected to a retractor shaft (a spool), so that the retractor shaft rotates in the winding direction. The retractor shaft rotates in the winding direction in this way, thereby a webbing (a webbing belt) is wound on the retractor shaft, so that tension of the webbing is increased, consequently a passenger body may be strongly restrained by the webbing.
In the pretensioner having the configuration as disclosed in JP-A No. 2000-313313, a pipe member such as stainless steel pipe is typically used for a cylinder (called “pipe” in JP-A No. 2000-313313 as described above) that is mounted with a gas generation unit called pressurized gas generation device or gas generator, and furthermore accommodates the rolling elements and a piston, which are moved by pressure of gas generated by the gas generation unit.
Since the cylinder is mounted with the gas generation unit as described above, the cylinder is deformed for positioning the gas generation unit in the cylinder.
However, the pipe member used for such a cylinder is a relatively expensive material. In addition, the pipe member is deformed for the positioning, causing further increase in cost.